1. Field of the Invention
The present invention relates to cathode ray tube monitors. In particular, the present invention is a cathode ray tube monitor in which a circuit board containing control circuitry for the cathode ray tube is attached to a mounting ring or collar which in turn is bonded to a back surface of the cathode ray tube.
2. Description of the Prior Art
Cathode ray tube (CRT) monitors are successfully used in a wide variety of applications, including conventional television, displays for computers, and a wide variety of other industrial, scientific and medical applications. Conventional CRT monitors include a cathode ray tube and drive circuitry which is mounted on a chassis. With advances in electronics, the size of many of the components of the drive circuitry of CRT monitors has been significantly reduced. Despite these improvements in the drive circuitry, very few attempts have been made to mount drive circuitry in any other fashion but the conventional chassis.
The Marholz U.S. Pat. No. 2,936,448, the Gray et al U.S. Pat. Nos. 3,119,900 and 3,139,485 and the Johnson et al U.S. Pat. No. 3,944,892 each show CRT monitors in which the circuit board containing drive circuitry is mounted coaxially over the neck of a cathode ray tube. While this provides somewhat more compact structure, all the patents require relatively complex mounting of the circuit board with straps, braces or the like. As a result, the advantages of eliminating the conventional chassis are not fully achieved by the devices of these patents.
The Marholz U.S. Pat. No. 2,936,448 shows a cylinder circumferentially placed around the neck portion of the cathode ray tube. Straps fixedly attached to the cylinder extend forward around the cathode ray tube to the front and are attached to an escutcheon by screws, thus holding the cylinder in place around the neck portion. This method is inconvenient for both original assembly and repair, since it requires four strips to secure the cylinder and each strap must be attached at one end to the cylinder and at the other to the escutcheon, requiring eight points of attachment.
The Gray et al U.S. Pat. Nos. 3,139,485 and 3,119,900 each show a circuit board apparently mounted around the neck portion of a cathode ray tube. The circuit boards are, however, also attached to a strap around the front portion of the cathode ray tube and to a support member comprising the bottom wall of a television cabinet. The Gray et al patents, like the Marholz patent, require several points of attachment for stable mounting of the circuit board.
The Johnson et al U.S. Pat. No. 3,944,892 shows a CRT display in which a rear circuit board 46 is mounted over the neck of the cathode ray tube. This rear circuit board is supported by side circuit boards which extend forward from the rear circuit board and parallel to the axis of the neck of the tube. The rear and side circuit boards form a box-like assembly surrounding the cathode ray tube with the side circuit boards being attached to the escutcheon by a rod. This arrangement is costly to manufacture and difficult to repair.